OBJECTIVE: To compare the habitual sedentary behavior (SB) and physical activity (PA) of older hip osteoarthritis patients before and after elective arthroplasty. METHODS: SB, PA and joint-specific disability of 16 patients (68.9 ± 6.8 years) were assessed by accelerometry and questionnaires before and 9 months after arthroplasty. RESULTS: All patients reported substantial postoperative improvements of their joint-related complaints (p ≤ 0.001). Accelerometry showed changes in neither daily SB (10–60 min sedentary bouts, p ≥ 0.569) nor in PA (steps, time in mild-to-vigorous activity and energy expenditure, p ≥ 0.255). Correlation analyses revealed that patients with severe preoperative disability showed a decrease in sedentary time, which was the opposite in patients with mild preoperative disability. CONCLUSION: SB and PA do not necessarily change after arthroplasty in older orthopedic patients. Even longer bouts of uninterrupted sitting, which are detrimental to health, do not decrease. Preoperative patient education is recommended to foster behavioral changes following elective arthroplasty.